1. Field of the Invention
The present invention relates to an opto-electronic alignment apparatus capable of being incorporated into left and right side vehicle exterior sideview mirrors to assist the driver in adjusting the mirrors to minimize the presence of any traffic "blind spots" or "blind zones" on either side of the vehicle.
2. Description of the Background Art
Passenger and commercial vehicles, e.g. automobiles and light trucks, are typically provided with an interior rearview mirror and exterior left and right side view mirrors with which the vehicle driver can view traffic to the sides and rear of the vehicle within certain fields of view dictated by the positioning of the mirrors. Typically, the interior rearview mirror can be manually adjusted about horizontal and vertical axes through its mount to the headliner or windshield to provide corresponding pitch and azimuth angle adjustment of the view through the vehicle rear window. Even when properly adjusted, the bordering structure of the rear window limits the view to either side. Consequently, vehicles are provided with left and right exterior rearview or sideview mirrors that are typically mounted at the junctures of the left and right windshield pillars with the adjacent front seat side windows. Mechanical or electro-mechanical, remote joystick controls are provided to allow the driver to adjust the sideview mirrors for azimuth (side to side about a vertical axis) and pitch (up and down about a horizontal axis perpendicular to the longitudinal axis of the vehicle). Improper adjustment of the sideview mirrors, particularly in azimuth angle results in wide blind zones or spots on either side of the vehicle.
Such blind zones or spots are widely described and depicted as shown, for example, in the FIGS. 1 and 4 of U.S. Pat. No. 5,033,835, incorporated by reference in its entirety. The blind zones on either side generally subtend an azimuth arc angle between the limits of the driver's peripheral vision while looking ahead and the left and right limits of the fields of view of the left and right sideview mirrors when the mirrors are aimed along the vehicle sides and a pitch angle generally bisected by the horizon. The blind zones are really cone-shaped tunnel areas expanding outward from the sides of the vehicle slightly downward from the eye level of the driver and away from the vehicle sides. Customarily, these right and left blind zones are referred to as blind spots, and that term will be used hereafter.
The current method of exterior sideview mirror alignment used on virtually all domestic and imported passenger vehicles simply relies on the driver's judgment as to the proper imagery he/she should see reflected by the sideview mirror. This is supposedly gained by experience with different settings. The vast majority of drivers erroneously believe that correct azimuth angle alignment is achieved when the side panels of their own vehicle are reflected back to them along one edge of the exterior sideview mirrors when they are in their normal driving position. This belief apparently arises from improper instruction during driver training or experience with older vehicles where the sideview mirrors were mounted forward on the fenders of the vehicle and reflected a wider field. It is also somewhat intuitive, albeit usually incorrect, to assume that this setting captures the entire view that cannot be seen through the inside rearview mirror.
After making this static adjustment, sooner or later, drivers experience an actual or near collision with vehicles in adjacent traffic lanes travelling in the blind spots. Through this experience, most people come to appreciate that there are left and right blind spots, but believe that the sideview mirrors are incapable of being adjusted to the correct setting. Instead, they crane their heads for a split second to look into the blind spot lane they intend to move into to make sure it is clear of traffic, distracting them from traffic ahead. The sideview mirrors become useless ornaments, and the distraction can cause rear end collisions.
To make matters worse, for styling and other reasons, sideview mirrors are frequently under-sized, do not extend outwardly of the vehicle sufficiently, and are positioned too close to the driver to allow a wide enough azimuth angle to be obtained in the assumed correct position. Even with these limitations, however, it is usually possible to correctly adjust the sideview mirrors to reflect back an image in the blind spot of a vehicle in an adjacent lane. The correct settings allow a driver to see overtaking vehicles in both adjacent lanes enter the sideview mirror images as they leave the rearview mirror image and remain in the sideview mirror image until they can be seen in the peripheral vision of the driver. Unfortunately, most drivers do not appreciate this dynamic manner of properly adjusting mirror settings, assuming that the sideview mirrors meet minimal size and positioning standards.
Frequently, two or more individuals may drive the same vehicle. While the interior rearview mirror may get readjusted by each driver, there is frequently no readjustment of the exterior sideview mirrors, even though a different driver is now controlling the vehicle. And, if one driver does adjust the sideview mirrors to his/her liking, the other should go through the same process but, typically, will forget to do so. The adjustments that are typically made by different drivers are pitch about the horizontal axis depending on the drivers' height or the pitch and azimuth, if the driver changes the seat height or distance from the steering wheel. In certain vehicles having memorized driver seat positions, the mirror pitch and azimuth positions are memorized with the seat positions as shown, for example, in U.S. Pat. Nos. 4,267,494, 4,625,329 and 4,727,302. Such systems do not necessarily provide the optimum position for eliminating blind spots, but instead rely on the drivers to make the initial settings that are memorized.
These problems with correctly aligning sideview mirrors to eliminate or minimize blind spots have attracted a great deal of attention at least in the patent literature as evidenced by the above-incorporated '835 patent. The '835 patent provides an auxiliary mirror built into a corner of the sideview mirror which images a reference point on the vehicle side to which the mirror is mounted when the main mirror is properly aligned to image the vehicle blind spot. In another form, the sideview mirror is first adjusted by the driver to image the reference point, and then the electro-mechanical system changes the alignment a preset amount to image the blind spot. A lamp on the adjustment mechanism lights when the final alignment position is achieved by the system.
The problem with the above approach is that having an auxiliary mirror on the front surface of the main mirror reduces the area for viewing blind spot obstructions. Also, the required target on the side of the vehicle may not always be clearly visible due to road grime on the vehicle or simply because of low ambient lighting. Finally, salient auxiliary mirrors and targets on the side of the vehicle large enough to be seen by the driver are anathema to automotive stylists.
Both wide viewing angle, static mounted, mirrors and dynamically movable sideview mirrors are the subjects of other patents, e.g. U.S. Pat. Nos. 4,019,812, 4,187,001, 4,318,590, 4,439,813, 4,575,202, 4,792,220 and 4,971,930. All of these proposed solutions require either bulky assemblies, distort the image in the field of view so that the driver does not see all the potential safety hazards in correct prospective, or are complex electro-mechanical systems with intermittent or continuously running motors and subsequent noise and vehicle power drain.
In addition, it has been proposed to alert the oncoming driver in the blind spot to the intention of the blinded driver to make a turn or lane change by adding turn signal indicators to the sideview mirror structure as disclosed, for example, in U.S. Pat. Nos. 4,906,085, 5,014,167 and 5,207,492. These forward mounted, auxiliary turn signals may alert an overtaking driver in the adjacent lane too late to be totally effective, and may even encourage the failure of drivers to properly set their sideview mirror azimuth angles. Moreover, due to their fields of view, if the sideview mirrors are not properly adjusted in the first place, the turn signals may not be seen by an overtaking vehicle.
The annual cost of side impact collisions in the United States caused by inappropriate turns or lane changes, exclusive of pain and suffering, has been estimated to be in the half billion dollar range by one major midwest based insurance company. Many of these accidents could be prevented with a simple aid for left and right sideview mirror alignments to embrace the blind spots peculiar to each vehicle model in the reflected images seen by the driver.
To be adapted by vehicle manufacturers, such an aid must be inexpensive, reliable, consume minimal power, and be able to be incorporated into a new or existing mirror housing subject to whatever styling considerations are imposed. To be accepted by the driving public, the aid must be simple to operate and not impact the cost of the sideview mirror system substantially. To be of practical value to the general public, the aid must inherently compensate, at least approximately, for variations in driver height and seat position. This inherent compensation should be automatic and occur as the vehicle operator uses the aid's optical cues during mirror alignment. Moreover, when used, the aid should provide positive feedback to the driver that assures him/her that the alignment is correct, even if it appears to the driver to be incorrect. These goals are all met with the embodiments of the present invention described in detail hereafter.